Before you start breeding, you’ll want to know how closely related the animals are. But what exactly is the difference between the inbreeding coefficient, kinship and AVK? What is inbreeding and what does it mean? And what do the terms ‘related’ and ‘kinship’ mean?
What is AVK?
AVK is a German term. It stands for AhnenVerlust-Koeffizient, or the ancestral loss coefficient. This measures how many ancestors appear twice in a five-generation pedigree. If every ancestor is unique, the AVK is 100%. However, if there has been line breeding in the past, the value is lower. If all five generations are complete, there are 62 animals in the pedigree. Suppose that 2 animals appear twice in the pedigree; then there are 62-2 = 60 unique animals remaining. The calculation is 60 divided by 62, multiplied by 100 per cent. The AVK is therefore 96.77%.
If the AVK is less than 100%, there is always inbreeding in an animal’s pedigree, but you cannot tell whether this inbreeding concerns the animal itself or one or more of its ancestors. An animal’s AVK is therefore not directly related to the animal’s inbreeding coefficient.
Where can you find the AVK?
The AVK is listed in the base details for each animal.
Tip:
Click on the pedigree. Animals with a yellow, blue or green dot next to their name appear more than once in the pedigree and result in a lower AVK.
What is kinship?
Kinship indicates the extent to which two animals are genetically similar. When two parent animals have offspring, they each pass on 50% of their genes to the young animal. The animal is therefore 50% related to its father and 50% related to its mother. The genes are passed down from generation to generation. The kinship coefficient is calculated by ZooEasy based on the pedigree. The percentages below apply if the parents are not related to each other. If they are related, the percentages are higher:
- Identical twins: 100%
- Full siblings: 50%
- Child and parent: 50%
- Half-siblings: 25%
- Child and grandparent: 25%
- Uncle or aunt and nephew or niece: 25%
- “Second-degree” cousin: 25%
- “First-degree” cousin: 12.5%
- Animal and great-grandparent: 12.5%
- No family relationship: 0%
In the case of a second cousin, the fathers are full brothers and the mothers are full sisters. In the case of a first cousin, two of the four parents are full brothers or sisters.
How do you calculate the kinship between animals?
- Go to [Breeding pairs]
- Click on Sample Pedigree
- Select a male and a female animal
- Click on Calculate kinship percentage
Tip:
Go to your pet’s base data. In the ‘Relatives’ tab, you can easily find all of the pet’s relatives, such as half-siblings, grandchildren, cousins, etc.
What is inbreeding?
Inbreeding occurs when two related animals (see kinship) are bred together. In other words, if the father and mother are related, the offspring is inbred. Mammals and birds have two strands of DNA, so each gene comes in pairs. Human DNA consists of approximately 40,000 gene pairs. Of each gene pair, one gene comes from the father and the other from the mother. The inbreeding coefficient is the probability that both parent animals will pass on exactly the same gene to their offspring. The inbreeding coefficient therefore calculates the probability that the animal will actually inherit two identical genes from both parents. That is the meaning of inbreeding.
Meaning of the inbreeding coefficient
- 0 = no inbreeding
- 0,25 = occurs, for example, when a full brother and sister are bred together
- 1 = full inbreeding: every pair of genes is identical
How do you calculate the inbreeding coefficient?
The inbreeding coefficient is listed in the base data for each animal.
How reliable is the data in your database?
The reliability of your figures depends on the data entered into the database. If you do not enter an animal’s parents, you will always get an inbreeding coefficient of 0 and an AVK of 100%. However, this does not necessarily mean that the animal has no inbreeding. Therefore, the more complete generations of animals you enter, the more reliable your figures will be.
The above information was provided by Dr P. Bijma of the Department of Animal Breeding and Genetics at Wageningen University & Research and incorporated into ZooEasy’s calculation methodology for inbreeding, kinship and AVK.